We saw AT&T open up a registration page for the Galaxy S 4 almost as soon as Samsung's presentation was over, but now that link is exposing a bit more information. Several tipsters let us know that for customers in certain areas, the website is now showing the 16GB GS 4 available for pre-order in White Frost or Black Mist. Anyone can see some of the details, including that it's promised to ship April 30th and has an off-contract pricetag of $639 ($199 w/ two-year agreement). Those who can get further in the ordering process report it's promised to arrive at their homes on or before May 3rd, with two-day shipping. Hit the link below if you're move to get your pre-order for Samsung's latest standard-bearer as soon as possible.